This invention relates to material distributing and mixing apparatus and particularly to stationary material distributing and mixing apparatus. Such stationary material mixing apparatus of different construction also have been known in the prior art variously as static mixers and interfacial surface generators.
Several varieties of prior art mixing apparatus are known and disclosed in the following U.S. Pat. Nos. 1,874,002; 3,051,452; 3,051,453; 3,182,965; 3,195,865; 3,206,170; 3,239,197; 3,286,992; 3,328,003; 3,358,749; 3,394,924; 3,404,869; 3,406,947; 3,583,678; 3,635,444; 3,643,927; 3,652,061; 3,664,638; 3,704,006; 3,733,057; and 3,751,009. Also of interest is French Patent No. 735,033 (1932). All of the above patents are herewith incorporated by reference. My prior copending application Ser. No. 428,865, is also incorporated herein by reference.
The prior art approaches typically involve expensive machining, molding, casting or other fabrication of the component mixer elements coupled with some type of permanent attachment between elements and a conduit. The resulting cost and difficulty of manufacture results in a relatively expensive end product. Moreover, many of the prior art mixers provide less than complete mixing and distributing particularly with respect to material flowing along the walls of the conduit. This so-called "wall-smearing"is related to the parabolic velocity profile of a fluid having laminar flow in a pipe: the fluid velocity is small or zero along the wall surfaces.
In applicant's above identified parent application, a plurality of self-nesting, abutting and axially overlapping elements are fitted into a conduit. While such a configuration is highly desirable where complete mixing of different materials is required, it has been found that certain applications require only a single element or alternatively, that the elements can be spaced apart and yet achieve results adequate for the application.
For example, where a substantial radial displacement of material flowing in a tube or pipe is required in as short a distance as possible with minimum pressure drop, the single mixing element according to the present invention is highly desirable.
A typical application for the single element is the equalization of temperature distribution in a heating or cooling application.
The invention is applicable not only to the mixing of two or more unlike materials but also the the re-distribution of a single material for thermal or other purposes. SUMMARY OF THE INVENTION
In accordance with the teachings of the present invention a stationary material mixing apparatus is provided comprising one or more elements fitted into a conduit. The elements can be inexpensively fabricated by punch pressing from flat sheets. The elements provide a close fit to the conduit walls when a slight "spring" is provided in the elements. No permanent connection between elements and the conduit wall is required but may be provided if desired. Thus, the conduit can be a flexible tube if required for a given application.
When combined with a material distribution head, particularly one with a coaxial feed, the mixing apparatus can be disposable to avoid any necessity to clean the apparatus after use with reactive materials.
As materials enter the element region a rotational vector is applied to the fluid stream by the oppositely bent ears. The subsequent flat region of the element causes the rotational vector to be transformed into a lateral or radial vector. The further set of bent ears imparts some additional lateral or radial vector and permits bilateral operation of the element so that materials can be passed in either direction through the conduit.
The inventive apparatus is useful for mixing and distributing virtually any materials including liquids, solids, gases, foams, etc.
Further advantages of the invention will be noted in the following detailed description.